Physico-Chemical Characteristics, Zooplankton Diversity And Fish Biodiversity Of Kakinada Bay And Coringa Mangrove Ecosystem, Andhra Pradesh, India

Abstract

The present study investigated the water quality parameters, zooplankton diversity, and fish biodiversity of the Gautami Godavari estuarine system and mangrove ecosystems of the Kakinada Bay and Coringa Wildlife Sanctuary region, Andhra Pradesh, India. Monthly sampling was conducted from July 2013 to June 2014 at six selected stations namely Kakinada Bay, Chollangi, Matlapalem, Ramanapalem, Coringa, and Bhairavapalem. Important physico-chemical parameters such as temperature, pH, dissolved oxygen, salinity, alkalinity, carbon dioxide, and hardness were analyzed using standard methods. Zooplankton samples were collected using plankton nets and fish diversity was assessed from fishermen catches and field collections.

The study revealed considerable seasonal and spatial variations in water quality characteristics under the influence of tidal fluctuations and monsoonal freshwater influx. Temperature varied from 26°C to 36°C, while pH remained slightly alkaline throughout the study period. Dissolved oxygen showed marked fluctuations with comparatively lower values during summer months. Salinity exhibited significant seasonal changes due to freshwater discharge during monsoon and marine water intrusion during dry periods. Higher alkalinity and hardness values were observed in Kakinada Bay owing to tidal influence and dissolved mineral content.

Zooplankton diversity was dominated by copepods followed by decapod larvae, chaetognaths, gastropod veligers, polychaete larvae, bivalve veligers, appendicularians, ostracods, and cladocerans. Seasonal abundance indicated that mangrove ecosystems provide highly productive nursery grounds supporting rich planktonic populations. Fish biodiversity analysis recorded 31 species belonging to 26 genera, 16 families, and 7 orders. Perciformes formed the dominant group followed by Cypriniformes and Clupeiformes. Commercially important fishes such as Mugil cephalus, Sardinella longiceps, Glossogobius giuris, and Oreochromis mossambicus were commonly observed.

The present investigation highlights the ecological significance of the Kakinada Bay and Coringa mangrove ecosystems in maintaining estuarine productivity, fishery resources, and biodiversity conservation. The study also provides baseline scientific information for future environmental monitoring, conservation planning, and sustainable management of the Godavari estuarine ecosystem.